package fy.filter;

import java.util.regex.Pattern;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

public class XssAndSqlHttpServletRequestWrapper extends HttpServletRequestWrapper {

	HttpServletRequest orgRequest = null;  

	public XssAndSqlHttpServletRequestWrapper(HttpServletRequest request) {
		super(request);
		orgRequest = request;  
	}

	/**
	 * 覆盖getParameter方法，将参数名和参数值都做xss & sql过滤。
	 * 如果需要获得原始的值，则通过super.getParameterValues(name)来获取
	 * getParameterNames,getParameterValues和getParameterMap也可能需要覆盖
	 */

	@Override

	public String getParameter(String name) {

		String value = super.getParameter(xssEncode(name));

		if (value != null) {
			value = xssEncode(value);
		}
		return value;
	}



	/**
	 * 覆盖getHeader方法，将参数名和参数值都做xss & sql过滤。
	 * 如果需要获得原始的值，则通过super.getHeaders(name)来获取 getHeaderNames 也可能需要覆盖
	 */

	@Override

	public String getHeader(String name) {
		String value = super.getHeader(xssEncode(name));
		if (value != null) {
			value = xssEncode(value);
		}
		return value;
	}



	/**
	 * 将容易引起xss & sql漏洞的半角字符直接替换成全角字符
	 *
	 * @param s
	 * @return
	 */

	private static String xssEncode(String s) {
		if (s == null || s.isEmpty()) {
			return s;
		} else {
			s = stripXSSAndSql(s);
		}
		StringBuilder sb = new StringBuilder(s.length() + 16);
		for (int i = 0; i < s.length(); i++) {
			char c = s.charAt(i);
			switch (c) {
			case '>':
				sb.append("＞");// 转义大于号
				break;
			case '<':
				sb.append("＜");// 转义小于号
				break;
			case '\'':
				sb.append("＇");// 转义单引号
				break;
			case '\"':
				sb.append("＂");// 转义双引号
				break;
			case '&':
				sb.append("＆");// 转义&
				break;
			case '#':
				sb.append("＃");// 转义#
				break;
			default:
				sb.append(c);
				break;
			}
		}
		return sb.toString();
	}



	/**
	 * 获取最原始的request
	 *
	 * @return
	 */

	public HttpServletRequest getOrgRequest() {
		return orgRequest;
	}



	/**
	 * 获取最原始的request的静态方法
	 *
	 * @return
	 */

	public static HttpServletRequest getOrgRequest(HttpServletRequest req) {
		if (req instanceof XssAndSqlHttpServletRequestWrapper) {
			return ((XssAndSqlHttpServletRequestWrapper) req).getOrgRequest();
		}
		return req;
	}



	/**
	 *
	 * 防止xss跨脚本攻击（替换，根据实际情况调整）
	 */

	public static String stripXSSAndSql(String value) {
		if (value != null) {  
			// NOTE: It's highly recommended to use the ESAPI library and  
			// uncomment the following line to  
			// avoid encoded attacks.  
			// value = ESAPI.encoder().canonicalize(value);  
			// Avoid null characters  
			/**         value = value.replaceAll("", "");***/  
			// Avoid anything between script tags  
			Pattern scriptPattern = Pattern.compile("<[\r\n| | ]*script[\r\n| | ]*>(.*?)</[\r\n| | ]*script[\r\n| | ]*>", Pattern.CASE_INSENSITIVE);  
			value = scriptPattern.matcher(value).replaceAll("");  
			// Avoid anything in a src="http://www.yihaomen.com/article/java/..." type of e-xpression  
			scriptPattern = Pattern.compile("src[\r\n| | ]*=[\r\n| | ]*[\\\"|\\\'](.*?)[\\\"|\\\']", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);  
			value = scriptPattern.matcher(value).replaceAll("");  
			// Remove any lonesome </script> tag  
			scriptPattern = Pattern.compile("</[\r\n| | ]*script[\r\n| | ]*>", Pattern.CASE_INSENSITIVE);  
			value = scriptPattern.matcher(value).replaceAll("");  
			// Remove any lonesome <script ...> tag  
			scriptPattern = Pattern.compile("<[\r\n| | ]*script(.*?)>", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);  
			value = scriptPattern.matcher(value).replaceAll("");  
			// Avoid eval(...) expressions  
			scriptPattern = Pattern.compile("eval\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);  
			value = scriptPattern.matcher(value).replaceAll("");  
			// Avoid e-xpression(...) expressions  
			scriptPattern = Pattern.compile("e-xpression\\((.*?)\\)", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);  
			value = scriptPattern.matcher(value).replaceAll("");  
			// Avoid javascript:... expressions  
			scriptPattern = Pattern.compile("javascript[\r\n| | ]*:[\r\n| | ]*", Pattern.CASE_INSENSITIVE);  
			value = scriptPattern.matcher(value).replaceAll("");  
			// Avoid vbscript:... expressions  
			scriptPattern = Pattern.compile("vbscript[\r\n| | ]*:[\r\n| | ]*", Pattern.CASE_INSENSITIVE);  
			value = scriptPattern.matcher(value).replaceAll("");  
			// Avoid οnlοad= expressions  
			scriptPattern = Pattern.compile("onload(.*?)=", Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);  
			value = scriptPattern.matcher(value).replaceAll(""); 
			value = value.trim();
		}  
		return value;  

	}



}
